Inches to cm converter

Type inches or centimeters and watch both update live.

Inches

Centimeters

1 in = 2.54 cm exactly, so multiply inches by 2.54 to get centimeters.

Inches to cm conversion table

Inches	Centimeters
1	2.54
2	5.08
3	7.62
4	10.16
5	12.7
6	15.24
7	17.78
8	20.32
9	22.86
10	25.4
11	27.94
12	30.48
13	33.02
14	35.56
15	38.1
16	40.64
17	43.18
18	45.72
19	48.26
20	50.8
21	53.34
22	55.88
23	58.42
24	60.96
25	63.5
26	66.04
27	68.58
28	71.12
29	73.66
30	76.2
31	78.74
32	81.28
33	83.82
34	86.36
35	88.9
36	91.44
40	101.6
48	121.92
60	152.4
72	182.88
84	213.36
100	254

Live two-way conversion
Exact to 2 decimal places
Table up to 100 in

How to convert inches to cm

Type a value in the inches box.
The centimeters box updates as you type.
Check the table below for a common length.

Why US rulers use sixteenths, not decimals

An inch on a US tape measure is usually marked down to a sixteenth, made by folding the inch in half four times: 1/2, 1/4, 1/8, 1/16. A centimeter ruler instead splits into ten equal millimeters, since the metric system is built entirely on powers of ten.

That difference is why converting a carpentry or sewing measurement means turning a fraction into a decimal first, then multiplying by 2.54. Halving by folding is also why the fraction system stuck around: it needs no measuring device at all, just a strip of material folded in half, then in half again.

Everyday lengths in inches and centimeters

Item	Inches	Centimeters
Standard ruler	12 in	30.48 cm
Yardstick	36 in	91.44 cm
US letter paper	8.5 x 11 in	21.59 x 27.94 cm
Quarter inch bolt	0.25 in	0.635 cm
55 inch TV, diagonal	55 in	139.7 cm

Letter paper is the clearest everyday mismatch between the two systems: it is sized in round inches in the US, but the centimeter figure it converts to, 21.59 by 27.94, is not a round metric size at all, unlike A4 paper, which is built from the metric system from the start.

A quick way to estimate without a calculator

Multiply inches by 2.5 for a fast estimate. It runs a little low: 36 inches times 2.5 gives 90, versus the exact 91.44 cm.
For anything under about 20 inches, that shortcut is usually within half a centimeter, close enough for a rough fit check.
Longer lengths need more care: a shortcut that is half a centimeter off at 20 inches can be several centimeters off by the time you reach a few yards, so switch to the exact figure for anything long.

Where this conversion comes up

US tools, screen sizes, bolts and lumber are specified in inches, while manuals, parts lists and shipping labels from outside the US almost always use centimeters. Converting inches to cm is the step that lets a US measurement fit into a metric spec sheet or a metric part.

US building codes, lumber dimensions and most home improvement tools stay in inches even on products exported worldwide, which is why a tape measure bought in the US often shows inches on one edge and cm on the other.

Inches to cm FAQ

How many cm is 1 inch?

1 inch equals exactly 2.54 cm.

How many cm is 12 inches?

12 inches equals 30.48 cm, which is 1 foot.

Is the inch to cm factor exact?

Yes. An inch has been defined as exactly 2.54 cm since 1959, so there is no rounding in the factor.

What is 5 foot 8 in cm?

5 feet 8 inches is 68 inches, which equals 172.72 cm.

How do I convert a fraction of an inch, like 3/8, to cm?

Turn it into a decimal first: 3/8 is 0.375, so 0.375 x 2.54 gives 0.95 cm.

How many cm is a yard?

A yard is 36 inches, which equals 91.44 cm.

Why do US rulers use fractions instead of decimals?

Imperial rulers split the inch in half repeatedly (into 1/2, 1/4, 1/8, 1/16), which is easy to mark by folding, while the metric system builds cm and mm on powers of ten instead.

Does this work for negative numbers?

Only lengths make sense here, so keep the value at zero or above. For a temperature or a signed measurement, use a different converter.